Using Ground Probes in Aquariums

Greg Gdowski

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Just so you know in case you ever go down this path again in the future, the ground probe doesn't need to get plugged into a GFCI outlet. The probe can be plugged in anywhere and it will still perform its intended function. I recommend powering the electrical equipment in your tank with a GFCI or 2, or 4 like I had at one time.
If whatever caused your issue is still possibly there you will want to be careful not to use a titanium heater with a 3 prong plug. They act exactly like ground probes.

I had not thought of a titanium heater as a substitute for a ground probe. Makes sense. It just never occurred to me.
 
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Brew12

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Brew, could this be some sort of battery effect? SaracensRugby, do you use any D.C pumps in your system.
I find it unlikely. No one really uses DC pumps in an hobby level aquarium. What we call DC pumps take 120v/220v AC and convert it to DC before converting it back to some form of AC at a lower voltage and varying frequency. That is how speed is controlled.
 

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The AC part is not in the water.
the DC pump is in the water

Has the resistance of a fish ever been measured?

Sorry for double post
 
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The AC part is not in the water.
the DC pump is in the water

Has the resistance of a fish ever been measured?

Sorry for double post
A true DC motor has to have an electrical connection between the rotor and the stator. Normally, this connection is made with carbon brushes. It is also critical that no water gets in around the rotor of a DC motor as it will short out.
Brushless DC motors are called DC because it is standard to rectify AC to DC and then use in converter or pulse generator to send an AC to the motor. If you send DC to a brushless DC motor it will not turn. So, if the motor is in the water, the AC part is in the water.

Yes, back when I looked there was quite a bit of information on the conductivity of fish. I pulled the numbers I used from a government website that was doing Navy research. Plenty of public universities have also done research on it.
 

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Brew,
I cant prove it, and not exactly the subject.
But i would almost be certain given electrical theory that if there was an appropriate voltage ( voltages ) in the salt water then a fish swimming amongst these differences in potential could very well feel some irritation.
Just to give an example to the readers how a voltage can be sensed by a person ( this is not dangerous )
Get a generic 9 volt alkaline battery used in portable electronic equipment and put your wet tongue on the two connectors on the end of the battery. You will feel a slight stinging on your tongue. ( i still use this method as a quick test to check if the battery is good haha)
In my opinion there are two parallel paths the current is taking ..... through your tongue and the other through your saliva. Which path the tongue is reacting to im not sure but either way it shows that at just 9 v it has an effect. Im not sure how salty saliva is as ive never bothered to test it LOL.
Anyway, im just putting this out there for comment.
What i would say, is im certain that fish would be better off without a voltage in the water than with it in the water.
Also, just another point any DC side of equipment that fails powered throught AC supply probably wont trip a ground fault device on the AC side.
 
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Brew12

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But i would almost be certain given electrical theory that if there was an appropriate voltage ( voltages ) in the salt water then a fish swimming amongst these differences in potential could very well feel some irritation.
It is possible and this is suspected of causing or contributing to HLLE but I have yet to see any positive connection made. Still speculation at this point.

Get a generic 9 volt alkaline battery used in portable electronic equipment and put your wet tongue on the two connectors on the end of the battery. You will feel a slight stinging on your tongue.
Just remember that we are talking millivolts of difference due to eddy's in the water, not volts. Probably only fractions of a millivolt. Its hard to say how much of an impact that has.

What i would say, is im certain that fish would be better off without a voltage in the water than with it in the water.
This is a bit of a rabbit hole I'm not sure is worth going down. For a voltage to be meaningful it must be referenced to another potential. A simple example of this is your homes 240V power. It is 240V between the two prongs but it is still only 120V to ground. I'll even use the analogy of the bird on the wire here. The bird doesn't know or care that he may be at 46,000V when he lands on a power line. He has nothing to reference that voltage to. So could a fish know if the water was 0V to ground or 100V to ground? Probably not. Now, it is a little different with induced voltages, but that is incredibly complex.

Also, just another point any DC side of equipment that fails powered throught AC supply probably wont trip a ground fault device on the AC side.
If the DC part itself fails, it should trip the GFCI. If it fails after where it converts that DC back to AC to send to the motor it is a different ballgame and depends on the technology used.
 

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It is possible and this is suspected of causing or contributing to HLLE but I have yet to see any positive connection made. Still speculation at this point.


Just remember that we are talking millivolts of difference due to eddy's in the water, not volts. Probably only fractions of a millivolt. Its hard to say how much of an impact that has.


This is a bit of a rabbit hole I'm not sure is worth going down. For a voltage to be meaningful it must be referenced to another potential. A simple example of this is your homes 240V power. It is 240V between the two prongs but it is still only 120V to ground. I'll even use the analogy of the bird on the wire here. The bird doesn't know or care that he may be at 46,000V when he lands on a power line. He has nothing to reference that voltage to. So could a fish know if the water was 0V to ground or 100V to ground? Probably not. Now, it is a little different with induced voltages, but that is incredibly complex.


If the DC part itself fails, it should trip the GFCI. If it fails after where it converts that DC back to AC to send to the motor it is a different ballgame and depends on the technology used.

Sorry, for the confusion Brew. Not the Bird! Lol.
I’m referring to a voltage applied with the ground probe, so that there is current flowing. I realise it would be small and fast before any circuit protection kicks in if it has adequate protection that is. But, just wondering the effects on the fish.

Yes, with eddies in the water column it would indeed be fractions of a millivolt I agree. I don’t really disagree with anything you are saying. I just wonder if nature has prepared them for voltages in seawater that can occur in our tanks. Your right in that all this can be a rabbit hole.

I’ve heard this anecdotal response from fish over many years now when a ground probe is installed from some very good sources. I’ve been in marine for just under 40 years and would love to have had the opportunity to do some electrical testing where this has occurred.

I am referring to the conversion of the of the of the DC back to AC for a brushless motor. I was trying to do what you did in simplifying for the reader. Every DC pump I have uses a AC to DC power supply, the DC side has no reference to the AC side. The DC then goes to the speed controller and then to the pump as AC. I don’t believe a fault at the pump which is in the water will trip any GFCI Brew as there is no coupling to the AC side anymore. Phew, this is making my head hurt.

I don’t have 120v to earth in my house?..... oh yeah, I live in Australia that’s right!
Plenty of food for thought on the effect of voltage on fish though.

Well, I took this of in another direction long enough. I use and recommend a ground probe for us human beans too! Lol
 
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Brad Miller

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This old debate again...LOL
What if this or what if that.....
Ok...
There are so many things associated with this topic, that for anyone to take a firm stance on the use of one just blows my mind.
Many men a lot smarter than anyone of us have debated this in scientific study and still to this day don't agree on the use of one.

Connect a grounding probe to your tank can open the door to many other adverse reactions to you and your tank.
You essentially just gave your tank a direct path to the earth ground of your house, which in turn grounded back to the power company and a ton of other things.
While this may seem like a good idea, it really now opens that door I mentioned above.
I don't know...maybe lightning strikes, where only 50% of that strike will probably be diverted to your earth ground outside...oh wait, that's connected to your tank now....

Reverse engineering the grounding rod idea seems to be a better way to approach the topic.
 

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All of my equipment has 3 prong plugs with a dedicated ground pin. I had my house rewired a few years ago, so I know all the outlets are wired properly. With such a system, why would I need a separate ground lead?

Seawitch submitted a new Article:

Using Ground Probes in Aquariums

Note from the Editor: Some time ago, our resident electrical guru, @Brew12, wrote a good article on the forum at the beginning of a discussion thread about using ground probes for your aquarium. As soon as I saw the article, I recognized that this deserved top billing. So, here, below, is our resident electrical guru's suggestions on ground probes in his own words. Hint: You need one.

~~~~~~~~~~~~~~~~~~~~~~~~

black-and-white-blurred-background-cables-1426702-jpg.975991

Photo by rawpixel.com from Pexels

Why is it that some people refuse to put a grounding probe in their aquarium? I've seen many arguments against using them, some of which are based on what I believe to be bad information.

I want to make the case for why every aquarium should have a grounding probe installed.
We have these beautiful aquariums full of salt water into which we place electrically operated equipment. Everyone has heard the phrase "Water and electricity don't mix" and it is especially true of salt water. Yet this doesn't have to be dangerous and a ground probe is key to making this safe.

An electrical shock occurs when current flows through a person. There are three main factors that impact the severity of the shock. The amount of current flowing through the person, the length of time they are being shocked, and the path the current takes through the body.

For a shock to occur, a person must be touching an energized conductor and a source to ground. The glass and acrylic most aquariums are made from are excellent insulators. If a pump or heater develops a fault in the salt water, it will raise all of the water in the aquarium to the same voltage as is available at the fault, typically close to 115V. If you are touching the metal housing of a light fixture or standing on wet concrete and touch the water, you become the best path for the current to take to get to ground. These shocks are most likely to take the most dangerous path, which is through our heart. It will go into the hand, through the heart, and either out the opposite hand or down through our legs.

high-24120_1280-png.975992



This is one way the ground probe keeps us safe. Electricity always takes the lowest resistance path to ground. The human body does have some resistance, so a properly maintained ground plug will always offer a lower resistance path to ground.

I would also make the argument that the use of a ground plug is important to the health of our marine fish, but not because of a risk of electrical shock. Scientists use electro-fishing techniques to collect or count fish populations by shocking fish. Electric eels hunt prey by shocking them with electricity. So why do I say marine fish are not at risk for being shocked? They live in salt water. Electric eels are a fresh water species and electro-fishing only works fresh water. In a fresh water environment the fish is more conductive than the water just like people are more conductive than air. You cannot shock a marine fish while it is in salt water since the water is more conductive than the fish. This doesn't mean that marine fish aren't affected by electricity.

It is a generalization to say that all of the salt water is at the same voltage in our aquariums. In reality, small differences in potential can exist within the water. Eddy currents of water will cause a difference in voltage. There will be a difference in potential caused by any air bubbles that may touch a fish. While these may not cause shocks, it can cause a serious irritation across the surface of the fish.

I would also point out that you do not need to have an electrical fault to have a harmful voltage in your aquarium. Any energized cord either running in the water or along the outside of the tank will create a voltage in the tank using a process called induction. This is why many people see a voltage in their aquariums without having a GFCI breaker trip. A ground probe will prevent any voltage from building up in the aquarium water, protecting our fish from these small voltage differences.

Grounding probes also protect our tank from another problem that is much harder to see and correct. If you have an electrical fault in your tank, there is a high probability that you have exposed copper in your system. This copper will corrode in salt water and the corrosion is accelerated when impacted by electricity. Even if you use a GFCI, the circuit will not trip on a fault until you have a source to ground. A ground probe will immediately provide that path to ground. If you do not have a ground probe installed, you could be leaching copper into your system for days or longer until a path to ground from your water is established.

The one argument against using ground probes I cannot counter is that it could provide a heat source during an electrical fault. If you have an electrical fault in a very narrow resistance range, and do not use GFCI protection, it can act like a heater. I know I wouldn't risk the safety of my family and friends in an effort to avoid this one scenario. I hope after reading this you won't either.

Does your aquarium system control panel look like this? Then get a ground probe.
shuttle-642404_1920-jpg.976113

This is a royalty-free image from Pixabay.

~~~~~~~~~~~

We encourage all our readers to join the Reef2Reef forum. It’s easy to register, free, and reefkeeping is much easier and more fun in a community of fellow aquarists. We pride ourselves on a warm and family-friendly forum where everyone is welcome. You will also find lots of contests and giveaways with our sponsors.

~~~~~~~~~~~

Author Profile: @Brew 12

Steven Frick has spent much more time under the ocean than keeping a small piece of it. He got his start in the electrical field in the US Navy Nuclear Power program as an electrician's mate. After 5 years of service on the submarine USS Henry M Jackson he finished his final 3+ years of service teaching electrical theory at the Knolls Atomic Power Laboratory.

Currently, he runs the projects and maintenance for the power distribution system of one of largest electrical consuming heavy industrial companies in the Southeastern United States. He wrote his sites' electrical safety policies and routinely acts as a consultant to other industrial facilities looking to improve their electrical safety programs. As someone who loves to both learn and teach, he has focused his attention on his newest hobby, reefing.
 

SteveC

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This old debate again...LOL
What if this or what if that.....
Ok...
There are so many things associated with this topic, that for anyone to take a firm stance on the use of one just blows my mind.
Many men a lot smarter than anyone of us have debated this in scientific study and still to this day don't agree on the use of one.

Connect a grounding probe to your tank can open the door to many other adverse reactions to you and your tank.
You essentially just gave your tank a direct path to the earth ground of your house, which in turn grounded back to the power company and a ton of other things.
While this may seem like a good idea, it really now opens that door I mentioned above.
I don't know...maybe lightning strikes, where only 50% of that strike will probably be diverted to your earth ground outside...oh wait, that's connected to your tank now....

Reverse engineering the grounding rod idea seems to be a better way to approach the topic.

Forgetting all the debate for and against, there is one thing that isnt debated and that is this.

WITHOUT a ground probe in a “ live “ tank you could be killed.
WITH a ground probe you are most unlikely to be killed.

That is enough reason for me to use one, I prefer life rather than the alternative.
I would think even the men smarter than us would choose With ground probe if asked to put their hand into a “ live” tank ...... or would they?

Just something you might ponder.... do you realise the ocean is grounded?
We were not debating against it by the way, until your comment , Lol
 
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Many men a lot smarter than anyone of us have debated this in scientific study and still to this day don't agree on the use of one.
I am not aware of any scientific studies done on the use of ground probes in aquaria. Do you have a link to them or know who has performed them? I would love to see them.
My personal feeling is that this is only not a clear debate because of bad information that is put out.
For instance, Professor Michelson wrote a few articles on the topic.
http://www.angel-strike.com/aquarium/GroundingProbes.html
Unfortunately, while he is technically accurate on many of the things he has written his post has 2 large issues. He never addresses that fish have a higher resistance than salt water. He also doesn't apply Faraday's law correctly on induced voltages which would mathematically prove why they are not an issue in our aquarium when using a ground probe. I've reached out to him a few times asking him to correct his post but he has never responded to my correspondence. I've also tried meeting him at IEEE events but he seems to no longer be active. He is a genuinely brilliant man and I have nothing but respect for him but that doesn't make him infallible.

There was also a video with 10's of thousands of reviews where a person tried to show how ineffective a ground probe was. People used to use his video in ground probe discussions to prove they were bad. The problem is that his methodology was defective. He did his testing using tap water instead of salt water. Fortunately, that video seems to have been taken down.

You essentially just gave your tank a direct path to the earth ground of your house, which in turn grounded back to the power company and a ton of other things.
I'm not sure why this would be a concern. The possibility of bad things happening to ungrounded systems is much higher than feedback through a ground.

I don't know...maybe lightning strikes, where only 50% of that strike will probably be diverted to your earth ground outside...oh wait, that's connected to your tank now....
Not an issue. If your tank rose a few hundred volts I doubt your fish would even notice. If it raised a few thousand volts they might, but you would also have lost ever electrical and electronic device in your house. Your aquarium would be the least of your problems. Your homes neutral is tied to ground inside your distribution panel. That big glass box that is your aquarium is much more likely to handle being pushed up to 5,000V than your powerheads and return pumps.


On a separate but interesting note, it looks like DC currents can actually help coral growth. I found this fascinating.
http://www.bbc.com/future/story/20150506-why-we-should-electrify-the-ocean
 
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Time to switch to titanium heaters... good tip
Make sure the heater has 3 prongs if you go this route. Some titanium heaters only have a 2 prong plug so the titanium housing isn't grounded.
 
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I am referring to the conversion of the of the of the DC back to AC for a brushless motor. I was trying to do what you did in simplifying for the reader. Every DC pump I have uses a AC to DC power supply, the DC side has no reference to the AC side. The DC then goes to the speed controller and then to the pump as AC. I don’t believe a fault at the pump which is in the water will trip any GFCI Brew as there is no coupling to the AC side anymore. Phew, this is making my head hurt.
I did some modeling of this and you're right, it made my head hurt too. It can trip a GFCI depending on how the rectifier/converter is set up related to the severity of the ground fault. It's not something that can be relied on. Fortunately, most controllers will detect these faults themselves and report an error.

I don’t have 120v to earth in my house?..... oh yeah, I live in Australia that’s right!
;Facepalm;Eggonface:oops:
 
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All of my equipment has 3 prong plugs with a dedicated ground pin. I had my house rewired a few years ago, so I know all the outlets are wired properly. With such a system, why would I need a separate ground lead?
Are you talking a separate ground lead in your home wiring or a separate ground lead as in the ground probe?

If you are talking about a ground probe, and absolutely everything that makes contact with your water has a 3 prong plug, then a ground probe wouldn't be necessary. I don't feel that this is the case for most people. I know I have multiple pieces of equipment in my tank that only have 2 prong plugs.
 
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@Brew12
Any preference on installing GFCI/DFCI breaker at the panel; or only at the receptacle?
Always wondered this- have had a lot of debate over it.
How about neither?
The problem with the breaker is that it can take out everything which will also harm the tank. If you rely on one receptacle that powers most of your loads you have the same issue. Not to mention that if it is behind your tank it can be very hard to reach to replace.
Instead, I make my own receptacles that are GFCI like I show here.
https://www.reef2reef.com/threads/diy-gfci-installation.342874/

I only use 2 on my current setup. My previous setup used 4 and I plugged each outlet pair into an aquarium controller outlet. This meant my controller could turn on and off each heater, my return pump, and my skimmer but each was on it's own GFCI so a trip of one didn't impact the other. I only use 2 now, one for each controller power bar but I have my loads spread out so that my tank will be fine for at least 12 hours if one trips and it will email me an alert.
 

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To the question posed to me on the last page, in the tank where I used the grounding probe and the fish had a negative reaction, I had a variable DC return pump (Jebao). Also was using Jebao powerheads. I know it is off this topic, but in my short experience I am not sure I trust cheaper products like jebao. Just me, not trying to bash any one brand. I know plenty of people have had good experience with those products so not trying to start a debate on that. That being said, @Brew12 would cheaper products have cheaper components, thereby be more likely to “leak” current into our tanks?

In my new(er) tank, I have an AC pump (eHeim). With Ecotech MP40QDs.
 
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That being said, @Brew12 would cheaper products have cheaper components, thereby be more likely to “leak” current into our tanks?
I'm not sure. The reality is that some of the higher end pumps are made by the same people who make the lower end pumps. It is possible that the better companies have higher QC standards but I can't say that with any certainty.
 

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I have a small quibble with what you said in your opening post. You said " Electricity always takes the lowest resistance path to ground." That suggests that it ignores the other paths.

That is somewhat misleading. Electricity takes all paths available to it. Most of the current will go through the lowest resistance path if the other paths are much higher in resistance. There will still be some current flowing through the other paths.
 

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